Artificial leg



(No Model.)

B. SCOTT. ARTIFICIAL LEG.

No. 302,433. Pate ited July 22, 1884.

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' UNITED STATES PATENT OFFICE EDWARD SCOTT, OF PITTSBURG, PENNSYLVANIA.

ARTIFICIAL LEG.

SPECIFICATION forming part of Letters Patent No. 302,433, dated July 22, 1884.

Application filed March 3, 1884. (No model.)

To all whom it may concern:

Be it known that I, EDWARD Soon, a sub ject of the Queen of Great Britain, and a resident of Pittsburg, Thirty-Second Ward, in the county of Allegheny and State of Pennsylvania, have made a new and useful improvement in that class of artificial legs wherein the knee is articulated or jointed, of which the following is a specification.

Heretofore all such legs have been constructed so that the action of the limb is brought about by simply lifting the leg ,with a sort of loose swinging forward movement sufficiently high to enable the foot to clear obstructions, and, by a progressive pitch of the body, straighten the leg and bring the foot down upon the ground preparatory to the next step; but as the movement of this knee'joint is only prevented from exceeding a certain limit in either direction by means of a positive stop at each end of a full swing at all intermediate points or positions, it remains free to move, and should the wearer stumble, no provision is made whereby he may suddenly stiffen the leg and use it as a brace or support to save himself from falling.

My invention consists of a combination, with the knee-joint of an artificial leg, of such a mechanical contrivance as will enable the wearer to suddenly check and firmly hold the leg stiff at any intermediate point between that represented by a straight standing leg and such angle of fiexure as is required to give a proper and natural position in sitting, and by a slight action of his shoulder either loosen the joint or suddenly check and hold the same at his convenience or pleasure in the act of walking.

To enable others to fully understand my invention, I will proceed to describe it by reference to the accompanying drawings, where- 1n-- Figure 1 represents a vertical section of an artificial leg, exhibiting thereina side elevation of my improvement; Fig. 2, a transverse vertical section "of such leg; Fig. 3 an enlarged detached view of my improved check device; Fig. 4, an edge view of the same.

Theartificial leg to which I propose to a ply my improvement may be constructed of 5c in an enlargement, e, having in its under edge a series of angular notches or catches, f. Af-' fixed in like manner in the lower portion, 9, of the leg is another metallic bar, h, provided at its upper with a short lever, 1;, pivoted thereto, one end of which is furnished with an angular hook, j, corresponding in shape and size with the notches f in the bar b above; and the hook j is constantly forced toward the aforesaid notches and-into them, when opportunityis given, by means of a spring, It, so attached to the lower bar,'h, as that its free end shall press againsta small projection, Z, on the under side of the lever, and thus keep it ready for immediate action. To the opposite end, m, of this hooked lever '11 is attached a cord or strap, p, that is intended to pass up over the shoulder of the wearer, and by suitable means be comfortably secured to his body in such a manner as that when he occupies a standing or upright position the tension of the cord 19 on the lever will be such as to withdraw and keep the hook j clear of the notches f f in the rigid bar above, and allow the knee-joint to swing free, as in other artificial legs; but should the wearer stumble in his walk, he will naturally stoop to save himself, and by thus depressing his shoulders relieve the tension on the cord p, whereupon the spring will so act upon the lever 2 as to cause its hook to engage one of the nearest notches f, and suddenly check the limber movement of the leg by holding it perfectly rigid and stiff until the wearer has an opportunity to recover himself and regain an upright standing position, upon which the joint will be released, that he may walk as before.

Having thus described the nature and construction of my invention, What I claim, and another portion of the leg, substantially in the desire to secure by Letters Patent, is manner shown, for the purposes hereinbefore The knee-joint of an artificial 1eg, in comset forth. bination with a spring lever or catch pro- EDWVARD SCOTT. 5 vided with a cord or strap for operating thev WVitnesses:

same, in conjunction with one or more notches R. R. LOWRY, secured to or arranged above the latch in H. T. MORRIS. 

